1. Technical Field of Invention
Embodiments in accordance with the invention relate generally to phototherapy. Phototherapy is a therapeutic physical modality using photons from the visible and infrared spectrum for tissue wound and burn healing, pain reduction, rhytide reduction (skin wrinkle) and hair follicle growth. It has also been shown to induce adipose cell membrane pore creation thereby allowing triglycerides, glycerol and free fatty acids to transit across the membrane into interstitial space. There have been more than 4000 studies published worldwide on the benefits of low level laser therapy (LLLT) and the effects observed with therapeutic lasers. Photo-bio-modulation increases ATP synthesis by changing the oxidation/reduction status of the mitochondria and activates the sodium/potassium pump thereby altering cell membrane permeability to calcium. Cell growth has been stimulated by an increase in cell metabolism. Higher levels of cell regeneration have been documented. LLLT has been shown to stimulate nerve function and the production of nitric oxide and endorphins. The neuropeptide substance P (SP) and histamine have been shown to be reduced thereby reducing local inflammatory response. LLLT also reduces the formation of acetylcholine, and bradikynin. LLLT has also been shown to reduce fibrous tissue formation. In photodynamic therapy (PDT) a photosensitizer is mixed with antibodies that are targeted to antigens on abnormal tissue. This mixture is then administered to the patient and binds with the antigens. Radio magnetic radiation having a wavelength corresponding to the absorption wavelength of the photosensitizer is then administered to the patient. This treatment reduces the size of the abnormal tissue.
2. Description of Related Art
Low level laser therapeutic instruments (LLLTI) achieve their therapeutic effect by emitting laser radiation at a chosen frequency or frequencies at a chosen power level for a chosen period of time at a chosen distance over a chosen area. Generally laser power is measured in watts, area is measured in centimeters (cm) squared, distance is measured in centimeters and time is measured in seconds. Therapeutic dosage is measured in watts multiplied by seconds divided by area in cm squared. Watts multiplied by seconds is defined as joules so dosage then is joules/cm squared. From this we see that to apply the larger dosage to the same area we can either increase the power of the laser or the length of time the laser light is applied, or both. Small hand held LLLTI require more time for the treatment of a given area because they must be moved repeatedly. However, small hand held laser instruments are useful for treating areas which are curved or have small hollows. Larger LLLTI with many more lasers cover a greater area but require cumbersome cooling apparatus to keep the lasers from overheating. Because most large LLLTI are not flexible they do not apply an even and precise dosage to any part of the treatment area which is curved or contains small hollows. In the case of both small LLLTI and most large area LLLTI patients are required to remain still, (seated or lying), while the treatment is applied. This is so because the instruments are held in place by either the patient's or technician's hand or laid onto the patient in a horizontal manner and kept in place by gravity. In the case of scanning LLLTI the laser beam is spread over a large area and requires a high power laser applied for a long period of time to administer the same dosage. Scanning LLLTI do not apply an even and precise dosage pattern because the laser diode is not a constant distance from the entire treatment area and because a scan line contains more laser energy in the center of the scan line than at either of the ends of the scan line. None of the LLLTI designs discussed above are easily transported and none of them can be used by a patient while performing typical household or office functions. Generally LLLTI require connection to mains power at the wall and have control systems which are floor standing. This limits the ability of a patient to move about or in most cases even sit up.
Several newer LLLTI designs have the ability to conform to the contours of a patient's body but are problematic for several reasons. These LLLTI position the lasers in contact with the patient's skin or very close to the skin. This positioning concentrates the laser beam in a small diameter at the center of the treatment area because the beam does not have room to expand over the entire treatment area. Some designs employ vertical cavity surface emitting lasers (VCSEL) or horizontal cavity surface emitting lasers (HCSEL) devices. These lasers project a very narrow beam with almost no beam divergence and cannot spread their light energy over the entire treatment area without optical lenses which these LLLTI do not employ. In addition these designs are made of non-breathable materials held in direct contact with the skin. In some cases these LLLTI are intended to be worn for many hours at a time and in some cases days at a time. This can cause skin rashes, be extremely uncomfortable, retard blood flow in the area, and cause sweating which can attenuate the laser light. Some of these LLLTI are programmed to energize at specific time intervals during the day and night. If the LLLTI has been removed by the patient in order to bathe or because of discomfort the LLLTI will not recognize this and run its programmed course of treatment without the patient being involved.
All LLLTI designs discussed above are problematic for eye safety. Laser light can damage the eye very quickly even at low power levels. Laser light in the visible spectrum is obvious to operator and patient and can be avoided with care. Laser light in the infrared spectrum is problematic because it is not obvious and does not cause pain until great damage has been done.
All semiconductor lasers produce heat when energized. Edge emitting lasers produce more heat than VCSEL or HCSEL devices because they are less efficient. Heat causes lasers to reduce their laser power output and to shift their laser light frequency to longer wavelengths. Referring to FIG. 17 of the drawings it is shown that physiological activity affected by laser light energy is not uniform but is greater in certain wavelengths than others. Also it is shown that by changing the frequency only slightly the effect of the laser light can be reduced by 80% or more. This reduction of the laser affect combined with the reduction of power output of the laser caused by rising temperature can render the LLLTI completely ineffective. Automatic power control systems which monitor the laser power output and try to maintain a constant power output exacerbate the problem by increasing the electrical energy supplied to the laser diode thereby further increasing the heat generated. Without cooling laser diodes can ‘run away’ and burn out immediately or have their life span reduced dramatically. The temperature of a patient's treatment area can vary significantly. The temperature of the hand or foot can be 20 degrees Fahrenheit cooler than the chest. Also room temperature will cause differences in skin temperature. Different body physiques will cause significant differences in skin temperature from one patient to the next. The only way to ensure that the laser diodes are lasing at the optimum frequency is with active temperature control.